Plumbing maxTouchPoints for Android.

ui/android/java/src/org/chromium/ui/base/TouchDevice.java

+// Copyright 2013 The Chromium Authors. All rights reserved.

[Ted C, 2014/03/05 21:14:26]

2014

[bokan, 2014/03/05 22:49:20]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.base;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+/**
+ * Simple proxy to let us query the touch device from C++
+ */
+@JNINamespace("ui")
+public class TouchDevice {

[Ted C, 2014/03/05 21:14:26]

since this only contains statics, maybe make a private constructor to avoid
creation.

[bokan, 2014/03/05 22:49:20]

Done.

+    /**
+     * Returns the number of supported touch points.
+     *
+     * @return Maximum supported touch points.
+     */
+    @CalledByNative
+    private static int maxTouchPoints(Context context) {
+        // Android only tells us if the device belongs to a "Touchscreen Class"
+        // which only guarantees a minimum number of touch points. Be
+        // conservative and return the minimum, checking membership from the
+        // highest class down.
+        if (context.getPackageManager().hasSystemFeature(
+                PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH_JAZZHAND)) {

[Ted C, 2014/03/05 21:14:26]

Ha!  Best constant name ever.

+            return 5;
+        } else if (context.getPackageManager().hasSystemFeature(
+                PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH_DISTINCT)) {
+            return 2;
+        } else if (context.getPackageManager().hasSystemFeature(
+                PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH)) {
+            return 2;
+        } else if (context.getPackageManager().hasSystemFeature(
+                PackageManager.FEATURE_TOUCHSCREEN)) {
+            return 1;
+        } else {
+            return 0;
+        }
+    }
+}